Rotary shaft control system



Jan. 19, 1965 LEO MORl ETAL 3,165,939

ROTARY SHAFT CONTROL SYSTEM Filed May 11, 1962 United States Patent ()fifice 3,i55,%9 Patented Jan. 19, 1965 3,165,939 ROTARY SHAFT CUNTROL SYSTEM Leo Moi-i, Setagaya-ku, Toiryo, isamu Niiirura, Hiratsuirashi, and Tsuyoshi Tshida, Kanagawa-hu, Yokohama, Japan, assignors to Tokyo Shibaura Electric Co., Ltd, Kawasaki-shit, Japan, a corporation of Japan Filed May 11, 1962, Ser. No. 194,021 iairns priority, application Japan, Feb. 17, 1962, 37/5,631 7 Claims. (Ci. 74365) The present invention relates to a rotary shaft control system and particulmly to an automatic rotary shaft control system adapted to impart to the rotary shaft approximately a predetermined rotation in one direction at a lower speed and subsequently rotate the rotary shaft in the opposite direction at a higher speed to restore the system to its starting position.

In operation of an automatic spectrophotometer, automatic light distribution photometer or other photometric device, each photometric measurement includes operating the monochromator to scan a spectral band from one end to the other at slow speed for the wave-length or operating the photometer to scan the photometric direction and restoring the system to the starting position ready for the next measurement. The scanning operation is usually effected by use of an electric motor. If the scanning be effected consecutively in opposite directions, the accuracy of measurement would be reduced because of mechanical inaccuracies such as backlash. Thus it has previously been necessary to scan only in one direction. Accordingly, each time one measurement has been completed, the scanning drive must be switched for manual operation to return the scanning system to its starting position. This has involved a number of disadvantages. First, the time required for photometric measurements has been extended especially when a large number of readings should be made. Further, the operator has been required to be watchful at all times to ascertain the com pletion of each measurement for switching the scanning drive and restoring the system to its starting position.

The present invention is intended to provide an improved rotary shaft control system which is capable of automatically controlling the operation of a rotary shaft as used in photometric measurements.

According to the present invention, a rotary shaft controlling system comprises two parallel drive mechanisms interposed between the rotary shaft and an electric motor for transmitting the rotation thereof to the rotary shaft. More specifically, the rotary shaft control system comprises a drive mechanism including a first solenoidoperated clutch and engageable with the rotary shaft to rotate the latter in one direction at a lower speed upon actuation of said first clutch and another drive mechanism including a second solenoid-operated clutch and engageable with the rotary shaft to rotate the latter in the opposite direction at a higher speed upon actuation of said second clutch. Also, a threaded shaft or lead shaft is provided which is rotatably engaged with the rotary shaft. Provided adjacent to the lead shaft are a pair of microswitches spaced from each other by a predetermined distance with a movable finger threadably engaged on said lead shaft for reciprocatory movement between a position opposite to the normally open contact of the first microswitch and another position opposite to the normally open contact of the second microswitch upon rotation of the lead shaft. According to the present invention, the reciprocatory movement of the movable finger is utilized to operate the two microswitches for changing the drive of the rotary shaft from slow rotation in one direction to quick rotation in the opposite direction by way of two electric relays associated with the microswitches.

The present invention has for its object to provide a control system of the kind described which is capable of automatically and smoothly changing the drive of a rotary shaft from slow rotation in one direction to quick rotation in the opposite direction.

Another object of the invention is to provide means for enabling such rotary shaft to automatically stop at a predetermined position.

A further object of the invention is to provide means for enabling the rotary shaft to stop at any desired position.

A still further object of the invention is to provide means for selectively starting such rotary shaft at any intermediate position for rotation in either of two opposite directions.

These and other objects and advantages of the present invention will be apparent from the following description when read with reference to the accompanying drawing, which diagrammatically illustrates one embodiment of the invention.

In the drawing, there is shown a rotary shaft control system including two drive shafts 4 and 5 operatively connected with the rotary shaft 1 by way of two bevel gearings 2 and 3, respectively. The shaft 5 is driven from an electric motor 6 by way of a speed reduction gear 7 at a suitable speed while the shaft 4 is driven by a gear in meshing engagement with a gear 8 of reduceddiameter mounted fast on the shaft 5. The two shafts 4 and 5 are disengageably connected with the rotary shaft by respective solenoid-operated clutches 10 and 11, thus forming two parallel drive mechanisms: one adapted to be operatively connected with the rotary shaft 1 upon actuation of the first solenoid-operated clutch 10 to transmit rotation of the electric motor to the rotary shaft in a manner so as to rotate the latter in one direction at a lower speed and the other adapted to be operatively connected with the rotary shaft 1 upon actuation of the second solenoid-operated clutch 11 to transmit rotation of the electric motor to the rotary shaft in a manner so as to rotate the latter at a higher speed in the opposite direction.

A threaded shaft or lead shaft 12 is journaled in bearings 13 and 14 and operatively engaged with the rotary shaft 1 by way of a bevel gearing 15. A movable finger 16 is threadably fitted on the lead shaft 12 in a manner so that upon rotation of the lead shaft 12 the movable finger 16 is translated laterally in either direction depending upon the direction of rotation of the lead shaft. It will be observed that, as the rotary shaft 1 is rotated by the drive shaft 4, the movable finger is moved at a relatively slow speed in the direction indicated by the arrow 17 and that, as the rotary shaft 1 is rotated by the drive shaft 5, the finger is moved at a relatively high speed in the direction indicated by the dotted arrow 18.

Arranged adjacent to the lead screw 12 are a pair of microswitches 19 and 20 spaced from each other by a predetermined distance and having respective switch elemen-ts a and d adapted to be actuated by the movable finger 16 and each having a normally open contact 0 or f and a normally closed contact b or e. As clearly shown in the drawing, the movable finger 16 is reciprocatorily movable between one end position 16a corresponding to the normally open contact 0 of the first microswitch 19 and the opposite end position 16b corresponding to the normally open contact 1 of the second microswitch 20. There are provided means including the movable finger 16 for restoring ,(urging, as by spring biasing) the first microswitch 19 to its normal position and actuating the second microswitch 20 to close its normally open contact 1 during forward travel of the movable finger 16 in the direction indicated by the arrow 17, and means including said movable finger 16 for restoring (urging, as by spring biasing) the second microswitch 29 to its normal position and actuating the first microswitch 19 to close its normally open contact during return travel of the movable finger 16 in the direction indicated by the dotted arrow 18.

A pushbutton type start switch 21 having three switch elements G, H and I is provided. A pushbutton type stop switch 22 and a pushbutton'type return switch 23 having respective switch elements I and K are also provided. The start and return switches 21 and 23 are each preferably of the non-locking type, being effective only while being pressed and self-restoring when released. The stop switch 22 is preferably of the locking type, remaining effective after it has once been pressed even if released thereafter.

A first relay 24 includes a solenoid L and two switch elements M and 'N and a second relay 25 includes a solenoid O and three switch elements P, Q and R. A power source B is provided for excitation of the respective solenoids L and O of the relays 24 and 25. Terminals s and s for the electric motor 6 are connectible with a separate power source (not shown). Numerals E E E E and E designate groundings of respective associated parts. The switch terminals of each of the switch elements G, H, I, J, K, M, N, P, Q and R are designated by the corresponding reference character in small letters with numerical suffixing. I

In the drawing, the circuit components are shown in position ready for operation. To start operation, the start switch 21 is first pressed to complete a circuit including the grounding E switch terminals g g and irh, solenoid L, switch terminals c1 q microswitch contacts e-d, switch terminals k k power source B and the grounding E Upon completion of this circuit, the first relay 24 is actuated to close the switch element M to complete the motor circuit including switch terminals m -m and the power terminals s s thereby to start the motor 6. At the same time, the switch element N is also closed to complete a circuit including the grounding E first solenoid-operated clutch 10, switch terminals r r and Il -n power source B and the grounding E to actuate the first solenoid-operated clutch starting the rotary shaft 1 to rotate slowly while simultaneously starting the movable finger 16 to move in the direction indicated by the arrow 17 at slow speed.

When the movable finger 16 reaches the position indicated at 16a, the first microswitch 19 is restored to close the normally closed contact b completing a circuit including the grounding E the normally closed contact I), switch terminals j j solenoid L, switch terminals q q normally closed contact e of the second microswitch 20, switch terminals k -k power source B and grounding E to selfhold the first relay 24 with the result that the rotary shaft 1 continues to rotate slowly and therefore the moving finger 16 continues to move slowly in the direction of the arrow 17 even after the pushbutton switch 21 has been released.

When the movable finger 16 reaches its position 16b, the second microswitch is immediately actuated to open the normally closed contact e and close the normally open contact 1''. Accordingly, the solenoid L of the first relay 24 is deenergized to open the switch elements M and N resulting in that the motor 6 stops to rotate and the first solenoid-operated clutch 10 is rendered inoperative, thus interrupting the rotation of the rotary shaft 1 and the lateral movement of the movable finger 16. On the other hand, the actuation of the second microswitch to close its normally open contact 1 forms a circuit including the grounding E the normally closed contact b of the first microswitch 19, switch terminals -1' and 11 41 solenoid O, resistor D, now closed normally-open contact f of the second microswitch 20, switch terminals k -k power source B and grounding E to actuatejhe second relay 25 to switch-over the switch elements P, Q and R. The switch-over of the element Q is effective to form a separate circuit effective to actuate the first relay including the grounding L normally closed contact 15 of the first microswitch, switch terminals j j solenoid L, switch terminals i i and q1q3, power source B and grounding E to reexcite the solenoid L of the. first relay 24, and thus the motor 6 again starts to rotate. Simultaneously with the above operations, the switch element R is actuated to connect its terminals 1'; and r to form a circuit including the earthing E second solenoid-operated clutch 11, switch terminals J' -r and 11 -21 power source B and the grounding E to actuate the second solenoid-operated clutch 11 with the first solenoid-operated clutch 16 held inoperative. Accordingly, the rotary shaft 1 starts to rotate at a higher speed in the opposite direction to move the movable finger 16 at a correspondingly high speed in the direction indicated by the arrow 13 toward its starting position.

The return movement of the movable finger 16 causes the second micrcswitch 20 to open its normally open contact f. The second relay 25, however, remains operative since the terminals 12 p of the switch element P connected in parallel with the normally open contact 1 are interconnected to form a self-holding circuit for the second relay.

The capacitor C and resistor D connected in parallel and in series, respectively, with the solenoid O of the second relay 25 are provided for delaying its operation thereby to ensure the restarting of the motor and actuation of the solenoid-operated clutches. Alternatively, a slow-acting relay may be substituted for the relay 25.

In quick return movement of the movable finger 16, when it moves past position 16a, it actuates the first microswitch 19 to open its normally closed contact b thereby to open the circuits for exciting the solenoids L and 0. As the result, the motor 6 stops its rotation and also the movable finger 16 stops at the position shown in solid lines ready for the next operation.

The rotary shaft 1 may be connected, for example, with a wavelength scanning mechanism for photometric measurement. On this occasion, the operator is only required when the movable finger 16 has restored its starting position to change the specimen and press the pushbutton of the start switch 21 to start the next measurement.

The rotary shaft 1 in rotation may be brought to a stop simply by pressing the pushbutton of the stop switch 22. By doing this, the terminals i of the switch element J are opened to s'nnultaneously break the exciting circuits for the solenoids L and O with the result that the motor is disconnected from the power source therefor and the circuits for the respective solenoid-operated clutches are opened, irrespective of the direction of movement of the movable finger 16 at the instant when the stop switch 22 has been operated,

If it is desired to return the movable finger when the rotary shaft is rotating slowly, the operator is only required to press the pushhutton of the return switch 23. This opens the terminals k k of the switch element K and hence the circuit for holding the solenoid L to stop the rotation of the motor 6 while rendering the solenoidoperated clutch 10 inoperative. At the same time, the terminals k and are connected to form another circuit for actuating the second relay including the grounding E first microswitch a-b, switch terminals j and h h solenoid O, resistor D, switch terminals k k power source B and grounding E to actuate the second relay 25 to close the switch elements 0 and R. As a result, the first relay 24 operates to start the motor 6 and simultaneously the solenoid-operated clutch 11 is actuated to re turn the movable finger at high speed.

If during the returning movement of the movable finger 16 the start switch 21 is operated, the switch element I is opened to break the third-mentioned circuit for actuating the first relay (E ab-j j Li i q q BE to stop the rotation of the motor 6 while rendering the solenoidoperated clutch 11 inoperative. The simultaneous opening of the switch element H breaks the self-holding circuit for the second relay to deenergize the solenoid 0 thereby to connect terminals 1' and r of the switch element R forming an operating circuit for the solenoid-operated clutch it). Simultaneousl the terminals q and q of the switch element Q are interconnected to energize the solenoid L thereby to restart the motor and slowly rotate the rotary shaft 1 by way of the solenoid-operated clutch 10.

As will be apparent from the foregoing, the rotary shaft control system according to the present invention is arranged so as to effect a predetermined range of slow rotation which is automatically changed at the end of the range into a high speed reverse rotation to return the system to its starting position completing one cycle of operation, ready for smoothly starting the next operational cycle without involving any mechanical stress or inaccuracy or any structural complexity. It will be noted that by use of the control system various types of measurement may be conducted to obtain highly accurate results without necessitating any complicated operation and that the time required for measurement is substantially reduced.

In addition, it will be appreciated that the control system of the present invention may readily incorporate a mechanism for interrupting the rotation of the rotary shaft at any desired point in its range of operation, a mechanism for reversing the rotation of the rotary shaft at any desired point during slow rotation in the forward direction, and a mechanism for reducing the speed of rotation of the rotary shaft at any desired point during rotation in the backward direction.

What is claimed is:

1. A rotary shaft control system comprising a rotary shaft rotatable in either direction, a drive motor, a drive mechanism including a first solenoid-operated clutch and operatively engaged with said rotary shaft upon actuation of said first solenoid-operated clutch to transmit the rotation of said drive motor to said rotary shaft in a manner so as to rotate the latter in one direction at one speed, another drive mechanism including a second solenoidoperated clutch and operatively engaged with said rotary shaft upon actuation of said second solenoid-operated clutch to transmit the rotation of said drive motor to said rotary shaft in a manner so as to rotate the latter in the opposite direction at a higher speed than said one speed, a threaded shaft operatively engaged with said rotary shaft, a first spring-loaded switch and a second spring-loaded switch both arranged adjacent to said threaded shaft and spaced apart from each other by a predetermined distance, each of said switches having a normally closed and a normally open contact, a movable finger engaged with said threaded shaft and adapted for reciprocatory movement between the two positions or" said first and second switches, said movable fin ger during forward travel adapted to move away from the first switch to permit restoring of the first springloaded switch to its normal position and to actuate the second spring loaded switch to close its normally open contact, said movable finger during return travel adapted to move away from the second switch to permit restoring of the second switch to its normal position and to actuate the first spring-loaded switch to close its normally open contact, a first relay and a first solenoid, a relay circuit including the normally closed contact of the second switch connected in series with the solenoid of the first relay and energizable uponactuation of said first relay, a motor circuit and a circuit including said first solenoidoperated clutch both connected to be completed upon actuation of said first relay, a self-holding circuit for said first relay including the normally closed contact of the first switch and the normally closed contact of the second switch connected in series with the solenoid of said first relay, a second relay and second solenoid, another relay circuit including the normally closed contact of the first switch and the normally open contact of the second switch connected in series with the solenoid of the second relay and operable when completed to actuate said second relay, two further circuits for actuating said first relay and for actuating said second solenoid-operated clutch both arranged to be completed upon actuation of saidsecond relay, and a self-holding circuit for said second relay arranged to be connected in parallel with said self-holding circuit for actuating said first relay upon actuation of said second relay.

2. A rotary shaft control system as claimed in claim 1 in which said second relay is of the slow-acting type;

3. A rotary shaft control system as claimed in claim 1 further comprising a stop switch operable to simultaneously open said self-holding circuit for actuating said first relay and said self-holding circuit for said second relay.

4. A rotary shaft control system as claimed in claim 1 further comprising a return switch operable to open said self-hoiding circuit for said first relay while connecting the solenoid of said second relay in series with the normally closed contact of the first switch to complete another circuit for actuating said second relay.

5. A rotary shaft control system as claimed in claim 1 including a start switch to energize the solenoid of the first relay and also including two additional switch elements operable to open said self-holding circuit for actuating said first relay and said self-holding circuit for said second relay, respectively, upon operation of said start switch during return travel of said movable finger.

6. A rotary shaft control system comprising a rotary shaft, a drive motor; a first drive mechanism between the motor and the shaft adapted for imparting drive rotation to the shaft in one direction at one speed, a first electrically actuable clutch effective at said first drive mechanism for connecting the motor to the shaft via the first mechanism, a second drive mechanism between the motor and the shaft adapted for imparting drive rotation to the shaft in the direction opposite to said one direction and at a speed different from said one speed, a second electrically actuable clutch effective at said second drive mechanism for connecting the motor to the shaft via the second mechanism, a threaded shaft operatively engaged with the rotary shaft for rotating therewith, a first switch and a second switch disposed in proximity with the threaded shaft and spaced a predetermined distance apant, a movable finger carried by the threaded shaft and adapted to engage the switches, a start switch, a first relay,'a first solenoid adapted to be energized through operation of the start switch to actuate the motor and first clutch via the first relay to drive the rotary shaft in said one direction and cause the movable finger to travel along the threaded shaft, a second relay, a second solenoid, a circuit for deenergizing the first solenoid and energizing the second solenoid via the second relay through operation of the second switch by said finger, a further circuit for actuating the second clutch via the second relay, a still further circuit for re-energizing the first solenoid to start the motor and drive the finger along the threaded shaft in the reverse direction at the different speed, and a stop circuit operable upon engagement of the first switch by the movable finger to deenergize the first solenoid and stop the motor.

7. The control system of claim 6, including a stop switch for interrupting the energizing circuits for both of the first and second solenoids to stop the motor with the finger at any position.

References Cited by the Examiner FOREIGN PATENTS 452,990 11/27 Germany.

DON A. WAITE, Primary Examiner.

BROUGHTON G. DURHAM, Examiner. 

1. A ROTARY SHAFT CONTROL SYSTEM COMPRISING A ROTARY SHAFT ROTATABLE IN EITHER DIRECTION A DRIVE MOTOR, A DRIVE MECHANISM INCLUDING A FIRST SOLENOID-OPERATED CLUTCH AND OPERATIVELY ENGAGED WITH SAID ROTARY SHAFT UPON ACTUATION OF SAID FIRST SOLENOID-OPERATED CLUTCH TO TRANSMIT THE ROTATION OF SAID DRIVE MOTOR TO SAID ROTARY SHAFT IN A MANNER SO AS TO ROTATE THE LATTER IN ONE DIRECTION AT ONE SPEED, ANOTHER DRIVE MECHANISM INCLUDING A SECOND SOLENOIDOPERATED CLUTCH AND OPERATIVELY ENGAGED WITH SAID ROTARY SHAFT UPON ACTUATION OF SAID SECOND SOLENOID-OPERATED CLUTCH TO TRANSMIT THE ROTATION OF SIAD DRIVE MOTOR TO SAID ROTARY SHAFT IN A MANNER SO AS TO ROTATE THE LATTER IN THE OPPOSITE DIRECTION AT A HIGHER SPEED THAN SAID ONE SPEED, A THREADED SHAFT OPERATIVELY ENGAGED WITH SAID ROTARY SHAFT, A FIRST SPRING-LOADED SWITCH AND A SECOND SPRING-LOADED SWITCH BOTH ARRANGED ADJACENT TO SAID THREADED SHAFT AND SPACED APART FROM EACH OTHER BY A PREDETERMINED DISTANCE, EACH OF SAID SWITCHES HAVING A NORMALLY CLOSED AND A NORMALLY OPEN CONTACT, A MOVABLE FINGER ENGAGED WITH SAID THREADED SHAFT AND ADAPTED FOR RECIPROCATORY MOVEMENT BETWEEN THE TWO POSITIONS OF SAID FIRST AND SECOND SWITCHES, SAID MOVABLE FINGER DURING FORWARD TRAVEL ADAPTED TO MOVE AWAY FROM THE FIRST SWITCH TO PERMIT RESTORING OF THE FIRST SPRINGLOADED SWITCH TO ITS NORMAL POSITION AND TO ACTUATE THE SECOND SPRING LOADED SWITCH TO CLOSE ITS NORMALLY OPEN CONTACT, SAID MOVABLE FINGER DURING RETURN TRAVEL ADAPTED TO MOVE AWAY FROM THE SECOND SWITCH TO PERMIT RESTORING OF THE SECOND SWITCH TO ITS NORMAL POSITION AND TO ACTUATE THE FIRST SPRING-LOADED SWITCH TO CLOSE ITS NORMALLY OPEN CONTACT, A FIRST RELAY AND A FIRST SOLENOID, A RELAY CIRCUIT INCLUDING THE NORMALLY CLOSED CONTACT OF THE SECOND SWITCH CONNECTED IN SERIES WITH THE SOLENOID OF THE FIRST RELAY AND ENERGIZABLE UPON ACTUATION OF SAID FIRST RELAY, A MOTOR CIRCUIT AND A CIRCUIT INCLUDING SAID FIRST SOLENOIDOPERATED CLUTCH BOTH CONNECTED TO BE COMPLETED UPON ACTUATION OF SAID FIRST RELAY, A SELF-HOLDING CIRCUIT FOR SAID FIRST RELAY INCLUDING THE NORMALLY CLOSED CONTACT OF THE FIRST SWITCH AND THE NORMALLY CLOSED CONTACT OF THE SECOND SWITCH CONNECTED IN SERIES WITH THE SOLENOID OF SAID FIRST RELAY, A SECOND RELAY AND SECOND SOLENOID, ANOTHER RELAY CIRCUIT INCLUDING THE NORMALLY CLOSED CONTACT OF THE FIRST SWITCH AND THE NORMALLY OPEN CONTACT OF THE FIRST SECOND SWITCH CONNECTED IN SERIES WITH THE SOLENOID OF THE SECOND RELAY AND OPERABLE WHEN COMPLETED TO ACTUATE SAID SECOND RELAY, TWO FURTHER CIRCUITS FOR ACTUATING SAID FIRST RELAY AND FOR ACTUATING SAID SECOND SOLENOID-OPERATED CLUTCH BOTH ARRANGED TO BE COMPLETED UPON ACTUATION OF SAID SECOND RELAY, AND A SELF-HOLDING CIRCUIT FOR SAID SECOND RELAY ARRANGED TO BE CONNECTED IN PARALLEL WITH SAID SELF-HOLDING CIRCUIT FOR ACTUATING SAID FIRST RELAY UPON ACTUATION OF SAID SECOND RELAY. 